Ground switch for motor vehicle batteries



p 1950 -J. E. DIGMAN 2,521,837

GROUND SWITCH FOR MOTOR VEHICLE BATTERIES Filed Dec. 10, 1948 JNVENTOR. Jomv 5.171 GMA/V BY A rroamrvs Patented Sept 12 p "GRVOUNDSWITCH roniiioron vE'HicL'E v A l surnames min E. Diginan, Takonia Park,: Md.

f p Applicationlleceinber 1o, 94g; aa t.t4,69

i 2 Claims (01. 200l53) My invention relates to a switch adapted to be interposed in the ground circuit of a motor vehicle battery whereby to open and close such circuit upon opening and closing of the switch. The

switch according tdthe invention comprises an improvement over the 'copending application of myself and Carl S. Davis, filed November 7, 1947, Serial No, 784,610, now Patent No. 2,481,829, granted September 13, 1949.

Withthe foregoing in view, it is an object of my invention to provide an improved ground switch for motor vehicle batteries. A-further object" is to provide an improved ground switch for motor vehicle batteries Which includes a switch body mounted on a motor vehicle frame, a movable contact carried by the switch body,- a'stationary contact carried by the switch body and insulated therefrom, said -stationary contact being adapted to be connected to the ground cable of a battery, a worm shaft threaded in said body and in operative engagement with said movable contact, and remote control means for pivoting said shaft whereby to 7 advance and retract the same and thereby move said movable contact into and out. of engagement with said stationary contact. Other objects and advantagesreside in the particular structure of the invention, combination wherein the invention is shown, described and claimed.

In the drawing:

Figure l is a plan view-ofthe switch according to the invention, showing the same in position on a motor vehicle frame, the motor vehicle I frame-being shown diagrammatically;

Figure 2 is a transverse vertical sectional view taken substantially on the plane of the line 2-2 of Figure 1;

Figure 3 is a longitudinal vertical sectional view taken substantially on the plane of the line 3-3 of Figure 1.

Referring specifically to the drawing, wherein like reference characters have been used throughout the several views to designate like parts, l designates generally any suitable metallic frame portion of a motor vehicle, such as a fire wall. The numeral I l designates generally a remotelylocated portion of the motor vehicle, such as the dashboard. A storage battery [2 for the motor vehicle is mounted in any suitable manner I thereon and includes a ground cable l3 detachably"s'ecured to one pole M 'of the battery in any suitable and/or well known manner. The) opposite end of the'ground ca'ble I3 is provided with the usual terminal l5 in the form of an; eye which normally'is detachably secured to any" suitable stud or the like, not shown, mounted onv the--frame of the motor' vehicle, whereby to groundthe'battery. I

'The'switch' according to the invention com prises a hollow cylindrical casing lfi providing a switch body which is preferably formed of current-conductingmaterial. The body I6 is open at on'e end and thereat provided with a pair of oppositelyedirected apertured ears) l'l whereby the "open end is adapted to be detachably con nected'by the set screws'l8 to the fire Wall l0 Of'llh vehicle in current-conducting relation thereto." The open end of the casing It may be closed by a dust cap [9, Figure 3, which may be held'in place by the engagement of the open end of thenhousing with the fire wall I 0.

- The stem of a headed stud of current-conducting material extends radially through the sidewallof the casing 16, but is insulated therefrom by the fianged collar 2! of insulating material which is concentrically disposed about the stem 20. The head for the stud 20 is disposed inwardly of the casing I6 and provides a stationary contact for the switch. The eye I5 for'theground cable I3 is adapted to encircle the stem .body of the stud and be rigidly secured thereto by the nuts 23 and washers 24 in a well known'manner.

A movable contact 25 is located inside of the casing' I6 and in the embodiment illustrated comprises a spring contact having its free end norbiased out of en'gagementwith the station ary'c ntact 22. opposite endof .the contact ZBissecured to'thecasing I6 in any suitable mannems'by the nut-and-bolt 26. The inner periphery of the wall of the casing l6 opposite to the head 22 of the stationary contact is formed with a radially inwardly-directed boss 21 which is provided with a cylindrical bore 28 in alignment with the stationary contact 22. A shaft 29 is slidable and rotatable in the bore 28. The shaft 29 is formed with a worm thread 30 of relatively long pitch whereby to provide means for advancing and retracting the shaft in the bore 28, as will appear later. Likewise, the casing 16 is provided with a pin 3| which intersects the bore 28 to provide an inner end for the pin slidably seatable in the thread 30. In the embodiment illustrated, the pin 31 comprises a set screw which may be locked in a suitable, adjusted position by any suitable means, such as the lock nut 32. In this connection, it should be noted that the pin 3| comprises means not only for causing advancing and retracting movement of the shaft 29 upon pivoting of the same in opposite directions, but also provides means for retaining the shaft in the bore 28 of the boss 21. The shaft 29 includes a free end projecting radially outwardly of the casing I 6 and formed with an integral rocker arm 34. Thefree end of the rocker arm 34 is connected in any suitable manner, as by the means 35, to a push-pull link 36 which preferably is in the form of a flexible or semi-rigid cable. link 36 is extended through any flexibleconduit 31 to the dashboard I I and'the remoteend there.-

of may be provided with a push-pull knob 38 suitably inscribed with identifying indicialit: The conduit 31 is adapted to be clipped to the periphery of the casing 16 by any suitable 'clip 40 which may be secured by a set screw 4|. a

On account of the long pitch of the thread 30, it, isnecessary to pivot the shaft, 29- only about-90 tocause the free inner end. of the shaft which bears, against theinovab'le contact to advance suflicientlyto move the spring contact 2-5v into. switch-closing engagement with, the stationary contact 22. A reverse pivoting of the, shaft 2.9

to a like degree-will break the circuit, whereby the battery I? is no longer grounded. Thus, it is arsimple matter for the car driver prior to leaving the car for a more or less, protracted period,jto pull outwardly on thehand piece or knob 38,whereby the rocker arm 34 and shaft 25 are pivoted suiiiciently topermit the spring con. tact 25 todiSengagcLthe stationary contact22. This arran ement, willv break every circuit in the automobile and prevent. any bleeding of the battery through undetected short circuits or the like. When the driver wisheslto use the car, it is a simple matter to, push. the .finger piece ,38, back, to its original position whereby to close. the switch and ground the battery 12.

While I have shown anddescribed what, isnow thought to be it preferred embodiment oi: the inventionfitis to be understood thatthe same is susceptible f or other forms and expressions. nseque I b. notlimit. myself tothe p ecise structure", shown and described hereinabove esceptas hereinafter claimed,

1. A1 wi h. for the ground, cable, Ora battery supportedon thefr'ame of, a motor vehicle com prising a current-conductive closed-end hollow cylindrical member having one end positioned in current-conducting relation to said frame'a'nd fixedly secured'yto the latter, a first contact supported within the wall of said cylinder andi'ingsulated'from' the latter, said contact, having one end projecting 'from"the wall of said "cylinder for connection "to said :ground' cable, ajsecond' contact arranged in ODPDSed aligned relation'witli ,the other face into touching relation with the facing end of. said first-named contact.

' 02. Aswitch for the ground cable of a battery supported on the frame of a motor vehicle comprising a: current-conductive closed-end hollow cylindrical member having one end positioned in' current-conducting relation to said frame and fixedly "secured to the latter, the first contact supported within the wall of said cylinder and insulated.fromi the latter, said contact having one'end projecting. from, the. wall of said cylinder for connection. to said ground cable, the second contact arrangedin opposedalignedrelationwith respect to said, first-named contact and mounted in the wall of said cylinder jfor'rocking movement, guide means carriedlinthewall of said cylinder and .operativelyengagingsaid second contact, said last-named means comprising a spiral groove formeilongitudinally of said second contact, a pinhavingone and extending through the wall of said cylinder and mounted for sliding movement into and out of, engagement with saidspiral groove, and; meanscarried by the other end of said pin for holding said pin in engagement with said spiralgroove, resilient contacting means carried by the wall of said cylinder and interposed between thefacing ends of said first and second-named contacts, the-other end of said second-named contact projecting from the wall REFERENCES ClTED The-following references are of record-in the file of this patent:

UNITED STATES PATENTS Number Name Date,

eas es I1ei-. l ..lMary17,1192? 1,995,945}, SGhilCl Mar. 26, 1935,

2,277,671 -Wi1 1iams ;et al.; Mar. 31, 19.42 

